SSR. This monograph received a strong response in the USSR and abroad. In 1963 it was published in English under the title "Parasitic Fauna of Freshwater Fish of the Ukrainian SSR". He continued to be actively interested in the research of Copepoda parasitica, and his latest monograph on the parasitic Copepoda of fish in the USSR was published for the Smithsonian Institution and the National Science Foundation (USA) by the Indian National Scientific Documentation Centre (1976). Proceeding from a series of solid scientific works on fish parasites (ichtyoparasitology) he formulated some theoretical fundamentals after complex studies on parasites of aquatic animals (hydroparasitology). As part of a scientific program, he identified studies needed on the ecology and development of the parasites of aquatic animals, studies on their influence on their host and vice versa, and studies on their dependence on abiotic and biotic factors. The theory of parasitocenosis, formulated by E. N. Pavlovsky, found a follower in A. P. Markevich. Attracted by Pavlovsky's concept of parasitocenosis, Markevich analyzed new facts obtained by parasitologists and microbiologists since Pavlovsky's publications, wrote several papers on this issue, and defined the task of parasitocenology as the "elucidation of objective patterns of life of parasitosymbiocenoses as well as biocenotic groupings of free-living parasite stages, in order to elaborate methods for directing the formation processes of parasitic communities" Markevich e created a school of parasitologists in Ukraine and sparked the interest of a number of zoologists and botanists in the research of Carpathian fauna and flora. For several years he was Vice-president and later President of the Biological Sciences Department of the Ukrainian SSR Academy of Sciences. He also made outstanding contributions to the research of parasite fauna of fish in Egypt, where he worked as expert and professor at Cairo University (periodically 1964 to 1967). International activities and honors In 1958 member of the delegation of the USSR to the Fifteenth International zoological congress in London (Great Britain). In 1959 visited Bulgaria, lecturing on practical questions of the phylogeny of invertebrate animals in the University of Sofia. In 1964-1965 professor of the Zoology Department of the Faculty of Science at Cairo University. In 1966-1967 expert on questions of parasitology in the National Scientific Center of the Arabic Republic of Egypt (ARE). In 1967 appointed an honoured member of the Polish Society of Parasitologists. In 1969 selected member of Academy of Zoology of India. In 1969 appointed